289 research outputs found

    The Virgo Cluster

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    In the era of precision cosmology the Virgo cluster takes on a new role in the cosmic distance scale. Its traditional role of testing the consistency of secondary distance indicators is replaced by an ensemble of distance measurements within the Local Supercluster united by a velocity field model obtained from redshift survey based reconstruction. WMAP leads us to see the Hubble Constant as one of six parameters in a standard model of cosmology with considerable covariance between parameters. Independent experiments, such as WMAP and the HST Key Project (and their successors) constrain these parameters.Comment: to appear in IAU Symposium 28

    100 million years after the Big Bang

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    Dark Energy Camera on the Blanco 4 meter telescope not only has the focal plane size the 4 meters were built for, but also has excellent near infrared response. A DECam Deep Fields program is outlined, which can reach M* galaxies at redshift 6 at a wavelength of one micron. What reionized the Universe, when did globular clusters form, were there very massive stars and how did they end, and how did supermassive black holes emerge a few hundred million years after the Big Bang ? These are some of the questions wide field high z surveys in the infrared will open to observational study.Comment: Presented at the 50th anniversary of Cerro Tololo Interamerican Observator
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